Guidelines and an article in the issue take on the thorny question of how obese type 2 patients must be for surgery to be effective in improving glycemic control.

The June issue of Diabetes Care, the journal of the American Diabetes Association (ADA), presents 32 recommendations on using what the authors call “metabolic surgery” to treat type 2 diabetes (T2D), which are presented as a joint statement by leading global diabetes organizations.1

The special issue, which also covers surgical treatment for type 1 disease and use of surgery in pediatric patients, is the strongest statement yet that bariatric surgery is not merely a way to help patients lose weight, but also is a proven way to treat a leading comorbidity.

ADA’s guidelines echo a recommendation issued the American Association of Clinical Endocrinologists (AACE), which last week released clinical practice guidelines for treating obesity. AACE called for surgery to treat obesity and diabetes for patients with a body mass index (BMI) of 30 kg/m2 if other treatments and lifestyle interventions have failed.2

Recasting the procedure as “metabolic surgery” gives these evidence-based techniques a name that suggests that weight loss is not the only, or even the primary consideration. “According to the authors, despite evidence being available for the powerful antidiabetes effects of surgery on type 2 diabetes, no guideline for diabetes care included surgical options,” wrote Max Bingham, PhD, in an introduction to the issue.

Bingham wrote that the guidance crafted by leading clinicians and researchers at the Diabetes Surgery Summit in September 2015 has received “an unprecedented level of support,” with endorsements from more than 30 professional organizations.1

“The new guidelines recognize for the first time surgery as a legitimate diabetes treatment and should inform physicians and policymakers about the appropriate selection of patients for surgical treatment,” he wrote. “Both practically and conceptually it is one of the greatest innovations in diabetes care in recent times.”

Authors David E. Cummings, MD, of the University of Washington, and Ricardo V. Cohen, MD, of Hospital Sao Camilo in Brazil, addressed the thorny question of how overweight a patient must be for surgery to be indicated. In their review of 11 randomized clinical trials (RCTs) comparing surgical vs lifestyle interventions for T2D remission and glycemic control, they found that results were “equally true for patients whose baseline BMI is below of above 35 kg/m2.”3

This finding informed the recommendation that metabolic surgery can be indicated on less obese patients; the authors report the speculation that rates of diabetes remission might be decline along with weight, “because such individuals lose less body weight after surgery.”

“However,” Cummings and Cohen write, “recent evidence from large meta-analyses and RCTs does not support that assertion.” The pair write that more long-term studies are needed to measure “hard” macrovascular/microvascular outcomes and mortality following surgery.3

What about overweight children with diabetes? In select cases, surgery makes sense, wrote Amy S. Shah, MD, MS, of Cincinnati Children’s Hospital and her co-authors.4

The authors found that evidence shows that T2D in adolescents “progresses rapidly and is more aggressive” than T2D in adults, and that because the patients are young there is more opportunity for comorbidities and organ damage over time.